1. Field of the Invention
The invention relates to cellulosic fibers of an improved dyeability and their production and use. More particularly, the invention relates to cellulosic fibers having an improved dyeability with an anionic dye, in which fibers a monomer containing a quarternary nitrogen atom is polymerized, as well as to a process for the production thereof and a process for discharge printing them.
2. Description of Prior Art
Cellulosic fibers are generally dyed with direct dyes or reactive dyes. These dyes have in general a low affinity and, thus, it is necessary to use an inorganic salt in a dyebath. However, even in the case where an inorganic salt is used, if a deep dyeing is to be obtained, a fair amount of the dye is retained in the dyebath which causes problems regarding environmental pollution and economy. Furthermore, direct dyes have a drawback in that they are inferior in wet fastness.
In the color discharge printing of cellulosic fibers, a vat dye or pigment is generally used as the effect color of printing to be added to the discharge printing paste. However, the use of vat dyes or pigments causes the following problems. When a vat dye is employed as the effect color of printing, sodium formaldehyde sulfoxylate, which is usually employed as a reducing agent, is unstable and, thus, its reducing capacity is decreased after the paste is applied to the material to be printed, thereby making the printing technically difficult and also making the acquisition of a clear color print difficult. When a pigment is employed, the resulting printings are liable to have a hard hand and a paint-like color shade, which degrade the quality of the resulting products. In particular, in the color discharge printing of textile materials of synthetic fiber/cellulosic fiber blends, the vat dyes which are built up in an alkaline medium can not be used as the effect color of printing in combination with dyes of the other classes and, thus, it is practically impossible to obtain a color discharge print on such blend materials.
Methods of treating cellulosic fiber materials with a quarternary ammonium group-containing polymer have hitherto been known, for example, in Japanese Patent Publications Nos. 53-23437, 53-24551 and 53-24552 and Japanese Laid-open Patent Specification No. 52-70196. In these methods, a film of the polymer is formed on the fiber surface. The treated materials have a hard hand and, in addition, cannot produce dyeings having a satisfactory color fastness since the dyeing sites applied by the treatment are easily fallen off by washing or rubbing.
On the other hand, methods of spinning a blend of a viscose solution and a quarternary ammonium group-containing polymer have been known, for example, in Japanese Laid-open Patent Specifications Nos. 53-35016, 53-35017 and 53-35018. However, these methods cannot be applied to natural cellulosic fibers.